4GLS and the Energy Recovery Linac Prototype Project at Daresbury Laboratory

4GLS is a novel next generation proposal for a UK national light source to be sited at Daresbury Laboratory, based on a superconducting energy recovery linac (ERL) with both high average current photon sources (undulators and bending magnets) and high peak current free electron lasers. Key features are a high gain, seeded FEL amplifier to generate XUV radiation and the prospect of advanced research arising from unique combinations of sources with femtosecond pulse structure. An R&D programme is addressing the challenging accelerator technology involved and a major part of this is a 35 MeV demonstrator, the ERL Prototype (ERLP) currently under construction. The 4GLS design activities are summarised, the ERLP described in detail and the 4GLS project status and plans explained.